[time-nuts] Second FTS4060 shows Drift, is it me? Good Links

Brooke Clarke brooke at pacific.net
Mon Feb 6 13:14:08 EST 2006


Sorry for the bad links, here are good ones:
Today's plot = http://www.pacificsites.com/~brooke/pdf/sn1013_850_Drift2.pdf
s/n 1227 29 Apr 2005 plot = 


Brooke Clarke wrote:

>A year ago I took apart the FTS4060 that was DOA (s/n 1013) because of 
>rough shipping and used it to figure out most of the interconnect 
>wiring.  A few months ago I put it back together with the thought of 
>selling it as a parts unit.  But first powered it up and found that it 
>now locked and seemed to be working so tried to set the C-field. 
>For the last couple of weeks it has shown a parabolic plot like s/n 
>1227, although this time the polarity is opposite that of s/n 1227 which 
>also showed drift, but that may be a setup difference.  A plot of s/n 
>1227 is at:   file:///C:/Webdocs/pdf/Cs_Drift0429.pdf 
>The equation for s/n 1013 is:
> y = 2.7943x2 - 302.64x + 8969.4 and the quality of fit is
>R2 = 0.9088.  The x-axis is in days and the y-axis is in ns. 
>The first derivative of the equation has a first term of 2 * 2.7943 * x 
>ns/day or +5.3E-14 seconds/seconds drift rate.
>Today's plot is at:   file:///C:/Webdocs/pdf/sn1013_850_Drift2.pdf
>The current setup is:
>SR620 time interval counter doing 500 averages (500 seconds = 8 1/3 
>Start from Motorola M12+T (9 ns jitter).
>Stop from FTS4060 1 MHz output.
>Manually enter into spreadsheet date and time of reading (usually not on 
>the 8 1/3 minute change, just a random time) and counter value.
>For most of the test the SR620 was using it's internal oscillator and 
>just recently I changed it to the PRS10 external standard but that does 
>not seem to have made any difference.
>Is there something I'm doing wrong that would cause apparent drift? 
>Thanks for any thoughts,
>Brooke Clarke, N6GCE

w/Java http://www.PRC68.com
w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml

More information about the time-nuts mailing list